Although alcohol clearly leads to alterations in mental processes and behavior, it is perhaps because these effects are so great and so pervasive that they have proven difficult to characterize. The global performance measures commonly used to document such effects, while demonstrating clearly their presence, often provide little information as to the specific locus or mechanism of effect. The present research aims to parse the separate effects of alcohol on peripheral nerve, sensory, cognitive and motor systems using event related brain electrical potentials. These potentials are studied within a broad context provided by performance, psychophysiological, neuropsychological, neuroradiological and neuropsychiatric data. The effects of alcohol are investigated in three classes of subjects: 1) The effects of acute administration are examined in normal volunteers with respect to dose-response relationships, the temporal course of effect, and relationship to blood alcohol levels; 2) Brain electrical activity is studied, in conjunction with neuropsychological data, in social drinkers in an attempt to assay the effects of moderate levels of alcohol consumption; 3) Abstaining alcoholics including those with alcoholism-related mental impairment, are studied to characterize the deficits, to examine the short- and long-term recovery effects, if any, during abstinence, and to examine the efficacy of various treatment strategies.